Examples

The term noir was coined in 1946 by French critics reviewing a group of American thrillers, including Billy Wilder's Double Indemnity and Otto Preminger's Laura, both from 1944, to mark a phenomenon they thought new to American cinema, a "harsh," "true to life" quality, a mood of "pessimism and despair."

It's no coincidence, I'd say, that Isaac Asimov wrote both science fiction and murder mysteries, or that the Illuminatus Trilogy and similar works appeal to many sf readers, or that noir is everywhere in strange fiction these days, even secondary world fantasy.